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<pre><span class="comment"> /****************************************************************************
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 #include &lt;QtGui&gt;

 #include &quot;mainwindow.h&quot;
 #include &quot;scribblearea.h&quot;

 MainWindow::MainWindow()
 {
     scribbleArea = new ScribbleArea;
     setCentralWidget(scribbleArea);

     createActions();
     createMenus();

     setWindowTitle(tr(&quot;Scribble&quot;));
     resize(500, 500);
 }

 void MainWindow::closeEvent(QCloseEvent *event)
 {
     if (maybeSave()) {
         event-&gt;accept();
     } else {
         event-&gt;ignore();
     }
 }

 void MainWindow::open()
 {
     if (maybeSave()) {
         QString fileName = QFileDialog::getOpenFileName(this,
                                    tr(&quot;Open File&quot;), QDir::currentPath());
         if (!fileName.isEmpty())
             scribbleArea-&gt;openImage(fileName);
     }
 }

 void MainWindow::save()
 {
     QAction *action = qobject_cast&lt;QAction *&gt;(sender());
     QByteArray fileFormat = action-&gt;data().toByteArray();
     saveFile(fileFormat);
 }

 void MainWindow::penColor()
 {
     QColor newColor = QColorDialog::getColor(scribbleArea-&gt;penColor());
     if (newColor.isValid())
         scribbleArea-&gt;setPenColor(newColor);
 }

 void MainWindow::penWidth()
 {
     bool ok;
     int newWidth = QInputDialog::getInteger(this, tr(&quot;Scribble&quot;),
                                             tr(&quot;Select pen width:&quot;),
                                             scribbleArea-&gt;penWidth(),
                                             1, 50, 1, &amp;ok);
     if (ok)
         scribbleArea-&gt;setPenWidth(newWidth);
 }

 void MainWindow::about()
 {
     QMessageBox::about(this, tr(&quot;About Scribble&quot;),
             tr(&quot;&lt;p&gt;The &lt;b&gt;Scribble&lt;/b&gt; example shows how to use QMainWindow as the &quot;
                &quot;base widget for an application, and how to reimplement some of &quot;
                &quot;QWidget's event handlers to receive the events generated for &quot;
                &quot;the application's widgets:&lt;/p&gt;&lt;p&gt; We reimplement the mouse event &quot;
                &quot;handlers to facilitate drawing, the paint event handler to &quot;
                &quot;update the application and the resize event handler to optimize &quot;
                &quot;the application's appearance. In addition we reimplement the &quot;
                &quot;close event handler to intercept the close events before &quot;
                &quot;terminating the application.&lt;/p&gt;&lt;p&gt; The example also demonstrates &quot;
                &quot;how to use QPainter to draw an image in real time, as well as &quot;
                &quot;to repaint widgets.&lt;/p&gt;&quot;));
 }

 void MainWindow::createActions()
 {
     openAct = new QAction(tr(&quot;&amp;Open...&quot;), this);
     openAct-&gt;setShortcut(tr(&quot;Ctrl+O&quot;));
     connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

     foreach (QByteArray format, QImageWriter::supportedImageFormats()) {
         QString text = tr(&quot;%1...&quot;).arg(QString(format).toUpper());

         QAction *action = new QAction(text, this);
         action-&gt;setData(format);
         connect(action, SIGNAL(triggered()), this, SLOT(save()));
         saveAsActs.append(action);
     }

     printAct = new QAction(tr(&quot;&amp;Print...&quot;), this);
     connect(printAct, SIGNAL(triggered()), scribbleArea, SLOT(print()));

     exitAct = new QAction(tr(&quot;E&amp;xit&quot;), this);
     exitAct-&gt;setShortcut(tr(&quot;Ctrl+Q&quot;));
     connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

     penColorAct = new QAction(tr(&quot;&amp;Pen Color...&quot;), this);
     connect(penColorAct, SIGNAL(triggered()), this, SLOT(penColor()));

     penWidthAct = new QAction(tr(&quot;Pen &amp;Width...&quot;), this);
     connect(penWidthAct, SIGNAL(triggered()), this, SLOT(penWidth()));

     clearScreenAct = new QAction(tr(&quot;&amp;Clear Screen&quot;), this);
     clearScreenAct-&gt;setShortcut(tr(&quot;Ctrl+L&quot;));
     connect(clearScreenAct, SIGNAL(triggered()),
             scribbleArea, SLOT(clearImage()));

     aboutAct = new QAction(tr(&quot;&amp;About&quot;), this);
     connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

     aboutQtAct = new QAction(tr(&quot;About &amp;Qt&quot;), this);
     connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
 }

 void MainWindow::createMenus()
 {
     saveAsMenu = new QMenu(tr(&quot;&amp;Save As&quot;), this);
     foreach (QAction *action, saveAsActs)
         saveAsMenu-&gt;addAction(action);

     fileMenu = new QMenu(tr(&quot;&amp;File&quot;), this);
     fileMenu-&gt;addAction(openAct);
     fileMenu-&gt;addMenu(saveAsMenu);
     fileMenu-&gt;addAction(printAct);
     fileMenu-&gt;addSeparator();
     fileMenu-&gt;addAction(exitAct);

     optionMenu = new QMenu(tr(&quot;&amp;Options&quot;), this);
     optionMenu-&gt;addAction(penColorAct);
     optionMenu-&gt;addAction(penWidthAct);
     optionMenu-&gt;addSeparator();
     optionMenu-&gt;addAction(clearScreenAct);

     helpMenu = new QMenu(tr(&quot;&amp;Help&quot;), this);
     helpMenu-&gt;addAction(aboutAct);
     helpMenu-&gt;addAction(aboutQtAct);

     menuBar()-&gt;addMenu(fileMenu);
     menuBar()-&gt;addMenu(optionMenu);
     menuBar()-&gt;addMenu(helpMenu);
 }

 bool MainWindow::maybeSave()
 {
     if (scribbleArea-&gt;isModified()) {
        QMessageBox::StandardButton ret;
        ret = QMessageBox::warning(this, tr(&quot;Scribble&quot;),
                           tr(&quot;The image has been modified.\n&quot;
                              &quot;Do you want to save your changes?&quot;),
                           QMessageBox::Save | QMessageBox::Discard
                           | QMessageBox::Cancel);
         if (ret == QMessageBox::Save) {
             return saveFile(&quot;png&quot;);
         } else if (ret == QMessageBox::Cancel) {
             return false;
         }
     }
     return true;
 }

 bool MainWindow::saveFile(const QByteArray &amp;fileFormat)
 {
     QString initialPath = QDir::currentPath() + &quot;/untitled.&quot; + fileFormat;

     QString fileName = QFileDialog::getSaveFileName(this, tr(&quot;Save As&quot;),
                                initialPath,
                                tr(&quot;%1 Files (*.%2);;All Files (*)&quot;)
                                .arg(QString(fileFormat.toUpper()))
                                .arg(QString(fileFormat)));
     if (fileName.isEmpty()) {
         return false;
     } else {
         return scribbleArea-&gt;saveImage(fileName, fileFormat);
     }
 }</pre>
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